Automatic conveying device



NOV. 21, 1967 s O ZANE 3,353,470

AUTOMATIC CONVEYING DEVICE Filed April. 19, 1965 5 Sheets-Sheet l N Q QQ \Q \9 I NVENTOR. 20mm of 0 Zfl/VE B g H z NOV. 21, R 5 Q ZANEAUTOMATIC CONVEYING DEVICE 5 Shets-Sheet 2 Filed April 19, 1965INVENTOR. m @ON/JLD J0. ZQ/VE BY 2 .4 H- Lds'v-L A ec-W7 Nov. 21, 1967R. S. O. ZANE AUTOMATIC CONVEYING DEVICE 5 Sheets-Sheet .5

Filed April 19, 1965 w n Q 3 R m v m Nov. 21, 1967 R. s. o. ZANE3,353,470 1 AUTOMATIC CONVEYING DEVICE Filed April 19, 1965 5Sheets-Sheet 4 INVENTOR I Fem/240 d? 0 Zq/vf BY 8 L. H-Ou Nov. 21, 1967R; S Q ZANE I 3,353,470

AUTOMATIC CONVEYING DEVICE Filed April 19, 1965 5 Sheets-Sheet 5 754 52mo 6 a 6.9 6 5 48 74 /50 INVENTOR.

,Qomqm J 0 ZQ/VE /48 BY 9 1 H- QM *1 /46 #5 ma dais/v7- United StatesPatent 3,353,476 AUTOMATIE CONVEYING DEVIQE Ronald S. O. Zane, 2572Hamner Ava,

Norco, Calif. 71760 Filed Apr. 19, 1965, Ser. No. 449,223 Claims. (CI.95-94) ABSTRACT OF THE DISCLOSURE A device for automatically developingdental X-ray plates. The device has a holder for X-ray plates suspendedfrom a rod, a pair of facing Walls with guideway channels sized tomatingly receive opposite ends of the rod, an elevator for moving therod up and down through a fixed distance, a series of X-ray developingbaths, a driving mechanism for the elevator, and an electrical controlsystem for automatically energizing the driving mechanism atpredetermined intervals. The guide-way channels serve to guide the X-rayplate holder from bath to bath, in proper sequence, as the elevator isdriven up and down by the driving mechanism at properly timed intervals,under the influence of the electrical control system, to assure anoptimum immersion time for X-ray plates in the holder in each of theX-ray developing baths.

This invention relates to a means capable of automatically carrying outthe successive immersion of objects to be liquid-treated forpredetermined periods of time in liquid baths. More particularly, theinvention relates to such a means having special adaptability for theautomatic development of exposed dental X-ray plates.

The common use of the X-ray as a tool for the examination of human teethby modern-day dentists is well known. Because of the current emphasis onfrequent dental check-ups for the early detection and treatment of toothdecay, and other dental ills, and other factors contributing to greaterX-ray use in dental ofi'ices and clinics, almost every dentist is nowfaced with the necessity of processing increasing numbers of dentalX-ray plates in the daily conduct of his practice. Such processinginvolves, of course, the developing of exposed X-ray plates, whichoperation is typically performed on the premises by a dental assistant,or other employee, and, upon occasion, by the dentist himself. X-raydeveloping work, as presently carried out, adds substantially to theoverhead cost of a dental oifice since it is a time-consuming chorewhich requires alert supervision throughout.

Exposed X-ray plates are now developed in a darkroom by first immersingthem in a developer solution for a preselected period of time, typicallyabout 3 and one-half minutes; removing them from the developer solutionand immersing them in a first water bath; removing them from the waterbath and placing them in a fix solution, normally for about minutes;taking them from the fix solution and placing them in a second waterbath; and finally removing them from the second Water bath and dryingthem in a stream of warm air, after which they are ready for thedentists inspection and use. The foregoing description does not includeall of the details of a typical X-ray plate developing operation (forexample, it makes no mention of temperature control of the variousliquid baths employed, nor of the water bath immersion, or rinsing,times) but it is complete enough to illustrate the time-consuming andburdensome nature of X-ray processing and the reason why it adds sosignificantly to the overhead cost of running a dental office. Inaddition to its overhead cost disadvantage, the X-ray plate developingprocedure as presently practiced has other drawbacks, perhaps lessdirectly manifested but just as real.

35,353,476 Patented Nov. 21, 1967 For example, as often happens during atypical working day in a busy dental office, when there is no oneimmediately available to handle a particular X-ray processing job, thedeveloping work must be postponed. This results in a work output, andconsequent earning rate, slowdown insofar as the dentist is concernedand, additionally, adds to the normal burdens of apprehension,inconvenience and time consumption borne by his patients as a naturalconsequence of their need for dental services.

I have now invented a means for automatically accomplishing thedevelopment of dental X-ray plates, by the use of which the foregoingdisadvantages of present-day manual developing techniques are largelyovercome. My automatic developing means, hereinafter referred to as theautomatic developer, is adapted to receive exposed X-ray plates andguide them through the necessary solution dipping, Water rinsing, anddrying steps of the developing procedure as described above. Theautomatic developer, in its preferred embodiment, is equipped withsignalling means for letting the operator know when the plates have beencompletely processed, thus reducing the necessity of supervision to aminimum.

It is thus a principal object of this invention to provide a means forautomatically accomplishing the development of exposed X-ray plates,thereby substantially eliminating the tedious, costly, andtime-consuming supervisory requirements of presently employed developingprocedures.

It is another object of the invention to provide an X-ray developingtechnique so characterized as to permit the immediate development ofexposed dental X-ray plates in dental ofiices with substantially nointerruption of higher priority work, professional or otherwise.

It is still another object of the invention to provide means to enabledentists to transmit dental examination results to patients morerapidly, thereby reducing the normal fear, inconvenience, and time lossconcomitants of dental work to a minimum.

Other objects, features and advantages of my invention will becomeapparent as the description thereof proceeds.

The structural character and manner of operation of my automaticdeveloper will be more readily understood by reference to theaccompanyin drawings, of which:

FIGURE 1 is a plan view of a preferred embodiment of the automaticdeveloper, showing a carrying rack for dental X-ray plates disposed insuitable starting position therein;

FIGURE 2 is a longitudinal section of the automatic developer takenalong line 2-2 of FIGURE 1;

FIGURE 3 is a view similar to the FIGURE 2 view, showing the X-ray platecarrying rack in a different position to illustrate a critical phase ofoperation of the auto matic developer;

FIGURE 4 is a section of the automatic developer, taken along line 4-4of FIGURE 2;

FIGURE 5 is a fragmentary View of the automatic developer in transversesection, taken along line 5-5 of FIGURE 2;

FIGURE 6 is an enlarged fragmentary view, mostly in section, showing thelinkage between certain moving parts of the automatic developer, takenalong line 6-6 of FIGURE 2;

FIGURE 7 is a fragmentary elevational view of a limit switch in anelectrical control circuit for the automatic developer and a moving partof the developer which makes actuating contact with the switch, takenalong line 7-7 of FIGURE 4;

FIGURE 8 is an enlarged, fragmentary elevational view, partly insection, showing the interlinkage of certain parts of a key mechanism inthe automatic developer, taken along line 8-8 in FIGURE 4;

end walls and 12, respectively. The bottom and walls of the housing areseparate members which are fastened together at their meeting edges bynail means, not shown.

It is not necessary that the housing be made of wood, and

any other structural material suitable for the purpose can besubstituted as desired. For example, the housing can be formed of asuitable plastic material, of which many types are well known, and, infact, as presently contemplated, this will be preferable to wood forcommercial production purposes.

Firmly glued to the oppositely facing inner surfaces of side walls 6 and8 of housing 2, in transversely'opposite and mirror-image relationship,are two arrayed groups of flat, precision shaped sections of Plexiglas,as shown in general at 14 and 16, respectively, on the drawings. ThePlexiglas sections are of equal thickness and so shaped and spaced aparton their backing side wall surfaces as to form a maze-like series ofslots, or passages, therebetween, suitable as guideways for moving partslater to be described. As will later appear evident, it is not necessarythat the guideway defining section pieces be made of Plexiglas and theycan be constructed of another plastic material, wood, metal, or thelike. All that is required of the material is that it be amenable tosome form of treatment to yield section pieces of proper shapes andsizes which can be afiixed to the walls of the housing in properorientation.

It should be pointed out that it is not necessary, for purposes of thisinvention, to affix separate section pieces to the housing walls to formguideways if equivalent guideways are otherwise obtainable. Thus, thepurposes of the inventionare satisfied if suitable guideways areincorporated directly in the walls of the housing, either by molding thewalls with appropriate slotted recesses or raised portions withslot-like passages of suitable character, therebetween. An equivalentexpedient is the use of secondary plates with built-in guideway patternsin lieu of Plexiglas section pieces. Where this expedient is employed,the secondary plates are molded, cast, or otherwise formed separatelyfrom the housing walls and later fastened to the walls in proper workingorientation. Other ways of achieving the same result will suggestthemselves to those skilled in the art from the teachings herein.

Disposed within housing 2 is an elevator 18, consisting of a frameworkof generally rectangular cross section having four upright slidemembers, 20, 22, 24 and 26, situated at its four corners, respectively.The upright slide members are of equal height, and they are tiedtogether at their upper ends by four metal straps, 28, 30, 32, and 34,respectively. As FIGURE 1 shows, tie straps 28 and 30 are of equallength and longer than straps 32 and 34, which are also of equal length.The upright slide members are of generally square cross section andhollow interior, somewhat resembling sections of square drain pipe, butwith important dilferences as will later be noted. The two shorter tiestraps, 32 and 34, are fastened, by rivet means, to separate pairs ofthe four upright slide members, respectively, and the same thing is trueof longer tie straps 28 and 30. The drawings clearly depictthe manner inwhich the tie straps and the upright slide members fit together to formelevator 18, hence little more need be said here on that subject.Suflice it to say, that the four upright slide members are so orientedas to dihedrally define the four corners of elevator 13, much as squarefence posts at the corners of a fence around a rectangular yarddihedrally define the volume enclosed by the outer surfaces of thefence, and that the long tie straps (28 and 33) are fastened to thefacing surfaces of two pairs of the slide members, whereas the short tiestraps (32 and 34) are fastened to the outer, oppositely facing,surfaces of two other pairs of the slide members, respectively. Thisconstruction of parts and manner of assembly is particularly wellillustrated in FIGURE 1. The reason for the inboard disposition of longtie straps 28 and 30, relative to the. volume defined by the cornerdihedral planes of elevator 18, will become evident as the descriptionof the invention, and particularly the further structural'details ofslide members 20, 22, 24' and 26, proceeds.

As FIGURES 2 and 3 show, long tie straps 28 and 30 are so positionedthat their upper edges fall in a common horizontal plane, and the samething is true of short tie straps 32 and 34. While the common horizontalplane of the upper edges of the long tie straps is different, in theillustrated embodiment of my invention, from that common to the upperedges of the short tie straps, this is a non-critical design feature ofthat particular embodiment, and it is within the scope of my inventionto utilize tie straps so sized and positioned as to have all of theirupper edges coplanar, or in different planes, or to reverse thedirection of elevation difference between the long tie straps and theshort ones from that depicted in the drawings. It is also, of course,within the scope of the invention to utilize an elevator of square,rather than rectangular, corner distribution, or to otherwise deviatefrom the design particulars of the drawings in noncritical ways. Manysuch deviations will be suggested to those skilled in the art from acomplete understanding of the manner of functioning of my automaticdeveloper as taught herein.

While the structural members of elevator 18 are of metallicconstruction, it is not necessary that this be the case, and theelevator parts can be fabricated of a suitable plastic or other materialadequate for the purpose if desired. In many instances aluminum is asatisfactory material for the elevator parts, but in other instances itmight be desirable to substitute stainless steel, an acidresistantplastic, or other material not subject to attack by corrosive or solventliquids therefor. The reason for the latter preference will soon becomeobvious,.if not already so, in view of the known liquid immersionutility of my automatic developer, hence will not be belabored here.

As will appear from the above description, elevator 18 is essentiallythe skeletal frame of a box-like structure without bottom-definingmembers. The elevator fits, bottom side down, within housing 2 inlaterally symmetrical relationship therein, but closer to one end of thehousing than the other. The clearances between the frame members of theelevator and the two side walls and nearer end 'wall of the housing,respectively, are relatively close for reasons which will later becomeapparent. The manner in which elevator 18 is supported within housing 2and, consistent with its name, raised and lowered therein, will bedescribed in detail below.

As previously indicated, uprightslide members 20, 22, 24 and 26 are ofhollow construction and generally square cross section, with two oftheir dihedrally related sides flush against a short and long one of thetie straps, respectively. The structural relationship between theuprights and tie straps is such that each of the former has an inwardlyfacing side disposed parallel to the inner surface of one of the sidewalls of housing 2. The side opposite to this, which is, of course,outwardly facing, is not flat, as are the other three sides of theupright slide members, but is, instead, of stepped configuration, asshown at 20a on the drawings, with an L-shaped lip 38 projectingoutwardly therefrom.-0ne leg 40 of the L shaped lip is in line with theriser-like portion of the 20a step configuration, and the other leg 42extends 5 parallel to the lower tread-like portion thereof for adistance equal to the tread width.

L-shaped lip 33 is integral with the upright slide member to which it isattached and the lip-riser-tread structure thereby formed defines achannel which receives rail-like member 44, the latter being anchoredagainst movement relative to housing 2 and described in greater detailbelow, in vertically slidable relationship for elevator stabilizationand guidance during its travels within the housing. Each of the otherthree upright slide members has a channel similar to that describedabove by obvious reference to slide member 20. The only differencesamong the slide member channels are that the mouths of the two disposedon the same side of elevator 18 face towards one another, the reason forwhich will subsequently become clear. Consequently, the foregoingdescription of the channel configuration of a specific one of theupright slide members is sufficient to teach the configurations of allmembers, and to avoid a confusing proliferation of symbols on thedrawing the parts of only the described channel are numbered thereon.

There is no difiiculty in fabricating slide members of the typedescribed, as l have discovered by forming such parts from thin gaugesheet aluminum utilizing bending, and other techniques well known tothose skilled in the art. It is not necessary that the members be madefrom aluminum or in the above-suggested manner, and, as previouslyindicated, it is preferable in many instances that they be made of amaterial more resistant than aluminum to attack by corrosive liquids.Neither is it necessary that the upright slide members be of thinwalled,hollow construction, as illustrated, and they can be solid, orthick-walled, if desired. The thin-walled construction is preferable,however, because of its lower weight characteristic.

Rail-like member 44, hereinafter referred to simply as rail, or track,44, which mates in vertically sliding relationship with the channel ofupright slide member 20, as heretofore indicated, is the projecting edgeof a thin strip of plexiglass fixedly superimposed, by glue means, overthe nearest (to upright slide member Ztl) end piece 46 of the group 14cluster of groove forming plcxiglass sections on side wall 6. While theproximity to each other of upright slide member 20, side wall 6 andgroup 14 of plexiglass sections, which makes the interengagement of theslide member channel and rail 44 possible, has not previously beenexpressly pointed out, it has been implicity disclosed by thedescriptions of those parts and the applicable portions of the drawingsincorporated therein by reference.

Turning again to the description of rail 44, plexiglass section 46 issufficiently thick, as FIGURE 1 shows, to hold the rail far enough awayfrom side wall 6 to permit nonbinding movement of the outer flange ofthe slide member 20 channel in the space therebetween during functioningof the pictured mechanism. The relative dimensions of the slide member20 channel and rail 44, and the positioning of each part with respect tothe other, are so adjusted as to permit free sliding movement of thechannel relative to the rail, while, at the same time, insuringdirectional guidance therefor. Each of the other three upright slidemembers, 22, 24 and 26, is positioned in matingly slidable engagementwith a counterpart member to rail 44 comprising the cantilevered edge ofa strip of plexigiass fixedly superimposed over the nearest end sectionof the applicable one of groups 14 and 16 of groove forming plexiglasssections. Thus as FIGURE 1 illustrates, the four corners of elevato 18are held in place by upright slide members with integral channels invertically sliding engagement with the projecting edges of fourcantilevered strips of plexiglas anchored to the four end sections,respectively, of groups 14 and 16 of the groove forming plexiglasssections.

Because of its corner support design, the length of elevator 18 is fixedby the spread distances (which are equal) along side walls 6 and 8 ofthe aforesaid groups 14 and 16, respectively, of plexiglass sections. Aspreviously indicated, and evident from the drawings, the two groups ofplexiglass sections are directly across from and mirror images of eachother, and hence of equal spread distance along their respective backingwalls. The sizes, shapes, and relative positions of the here-involvedparts are so determined as to permit free up-and-down movement ofelevator 18 within housing 2 under the guiding influence of rail 44 andits three structural counterparts of previous reference, which act ascorner holding means to maintain the elevator on course during itsoperating periods and furnish confining support therefor at other times.

The illustrated embodiment of my invention functions by causing elevator18 to rise automatically from its lowest point through a fixed verticaldistance to a maximum elevation and then return, at predetermined timeintervals. Each lift of the elevator carries a load of X-ray plates outof a liquid bath stationed at its lower terminus, and with the aid of acooperating member with oppositely oriented projections (later describedin detail) which ride in the grooves or channels between the plexiglasssections of the aforesaid groups 14 and 16 thereof, the moving elevatoradvances the X-ray plates to either another liquid bath or to a dryingzone, depending upon the stage of operation, during each of its roundtrip travel cycles.

Hereinafter the aforesaid grooves or channels between groups 14 and 16of the plexiglass sections will be referred to as guideways 14a and 16a,respectively. Everything previously said regarding the class of suitablematerials of construction for the guideways 14a and 16a definingmembers, the plexiglass section pieces of repeated previous reference,is equally applicable with respect to rail 44 and its three structuralcounterparts, also of repeated previous reference, for keeping elevator13 on the track. It is not necessary that these guide rails be supportedas shown in the drawings, and described above by reference thereto, andthey can be supported by any suitable means occurring to one skilled inthe art in the light of the present teachings.

Elevator upright slide members 20, 22, 24 and 26 are connected at theirlowe ends to rods 48, 50, 52 and 54, respectively, which, in turn, arepivotally anchored to pivot pins 66, 68, '70 and 72, respectively. AsFIGURES l and 4 show especially well, the thus-pivoted rods 48, 50, 52and 54 are all disposed planarly parallel to the side walls of housing 2and each is spaced, for the most part, away from the nearest side wallsurface the same distance, this being substantially equal to theperpendicular distance of the linkage joint between it and its coopcrating slide member on elevator 18 from the wall surface. The two rodsnearest each side wall (rods 48 and 5t), and 52 and 54, respectively)extend outwardly in different direction from a common moving pivotengagement site at one end of a shaft 64 perpendicular thereto, saidshaft being of sufiicient length to extend transversely across housing 2and form such moving pivotal contact at both ends with the two pairs ofrods, respectively, to oute end linkage with their respectivelycooperating elevator slide members.

The subject rods, 48, 50, 52 and 54, are made of relatively thin strapmetal, and each is characterized by a slight offset bend, shown at a, b,c and d on the drawings for the four rods, respectively, between itsfixed pivot point (that is, where it is pivotally anchored by one of theaforesaid pivot pins) and its moving pivot engagement site with shaft64. As the drawings illustrate, the lever arm distance between the fixedpivot point of each r d and its inner end juncture with shaft 64 issubstantially shorter than that between the pivot point and the site ofthe outer end interlinkage of the rod with the elevator 18 structure ofprevious description. There is nothing magical about this particularlever arm ratio and it is a design feature of the illustrated embodimentof my invention which can be altered as desired, so long as the changeis not so drastic as to render the device inoperable. In thisconnection, and as those skilled in the-art will appreciate, variationof the aforesaid lever arm ratio is a legitimate way to control the liftheight of elevator 18 and therefore well within the noncriticalmodification areas, and hence scope, of my invention.

The principal reason for the offset configurations of the subject rodsis to permit the inner termini of each pair coengaged with the same endof shaft 64 to so coengage while their main portions remain incoalignment. Such coalignment is, at least to some extent, necessitatedby the equal spacing of the upright slide members of elevator 18 fromthe side walls of the housing, and the manner of linkage of those rodsto those members. The offset bends in each pair of the 48, 50, 52 and 54rods connected to the same end of shaft 64 extend oppositely from eachother, as shown particularly well in FIGURES 1 and 4, for reasonsobviousin the light of the foregoing.

For reasons which will be increasingly appreciated as the description ofthe invention proceeds, those pivot points of rods 48, 50, 52 and 5situated on oppositely facing surfaces of sidewalls 6 and 8 of housing 2are in mirror-image relationship to each other. This, plus the fact,implicit from the foregoing, that shaft 64 must of necessity behorizontally disposed, makes it obvious that the members of each pair ofthe aforesaid rods extending in the same direction from the shaft, andtherefore necessarily disposed at opposite sides of the housing,respectively, are parallel to each other at all times during theoperation of the pictured mechanism. Since, as will appear presently,there is another pivoted rod in that mechanism, rods 48, 50, 52 and 54will, to avoid confusion, be hereinafter referred to as side pivot rodsor pivoted side rods. Pivot pins 66, 68, 7 0 and 72 for the side Pivotrods are screws which pass freely through properly sized and locatedopenings in their respectively associated rods. The screws arethreadedly achored to two wooden spacer blocks 74 and 76 of equal sizeand configuration attached to side walls 6 and 8, respectively, intransversely opposite relationship within housing 2; screws 66 and 68being fastened to spacer block 74 and screws 70 and 72 to spacer block76. The spacer blocks are affixed to the side walls of the housing byglue means and they provide anchor bases for pivot screws 66, 68, 78 and72 sufiiciently offset from the side Walls to bring the pivoted siderods into their proper positions of alignment relative to the elevatorupright slide members with which they cooperate. Each of the screws 66,68, 70 and 72 has a washer between its head and the side rod for whichit serves as a pivot pin, and a couple of washers between its anchorbase spacer block and the side of the rod opposite the screw head. Thescrews are not drawn sufficiently tight against their respectivelyadjacent washers to bind, but provide snug fitting pivot joints whileleaving sufficient tolerances between the various parts of the joints toallow free movement between the side rods and their individuallysandwiching Washers. The washers between the spacer blocks and the siderods, in addition to providing low friction flanking surfaces for theside rods as they pivot around their pins, serve as shims to compensatefor the offset deviations of the rods oriented with the deviation bendstoward the housing side walls, and thus insure pivotal freedom of thoserods by holding them free of binding contact with spacer blocks 74 and76.

The up-and-down movement of elevator 18 within housing 2 and thecharacter of the mechanical interplay between the lower end of each ofthe upright side members of the elevator and the outer end of itscooperating side rod requires a sliding pivot type of interlinkage forjoinder, of those parts. For purposes of simplicity, this interlinkagemechanism, which is identical for each of the four pairs of connectedparts, will be described by specific reference to the joint betweenupright slide member 20 and side rod 48, this particular one being shownin enlargement in FIGURE 6. Basically, the joint is nothing more than apin fixedly secured to upright slide member 20 and passing through aslotted opening of previous reference near the outer end of side rod 48in perpendicular relationship to the rod. More specifically, the pin isthe shank of a small bolt 78, which passes through aligned openings inopposite walls of upright slide member 20 so located as to assure theperpendicular pin-side rod relationship above referred to and depictedin the drawings.

Bolt 78 is secured in place by means of a nut 80 threaded thereon tosnug fitting tightness against the outer surface of the wall of slidemember 20 through which the shank protrudes. The receptive slot for boltpin 78 in side rod 48, shown at 82 on the drawings, is of sufficientwidth to permit non-binding passage of the bolt pin therethrough, but ofa length substantially greater than this, as the drawings illustrate.The reason for this, as will subsequently become more apparent, is toprovide travel room for bolt pin 78 in the slot as the lever armdistance on the rod from its pivot point at screw 66 to the pressureacting point on elevator 18 varies with the vertical displacement of theelevator during its travel cycles.

As the drawings show, the aforesaid slot is transversely centered inside rod 48. The lower walls of upright slide member 20 across the pathof side rod 48 in its illustrated position are slotted from the bottomto a sufiicient height to permit unhindered movement, of the indicatedpivotal and sliding nature, of side rod 48 relative to bolt pin 78during operation of the automatic developer. The resulting slots in theslide member walls, shown at 84 and 86, respectively, on FIGURE 6, arein proper alignment with the lay of side rod 48 and their widths, whichare equal, suificientiy greater than the thickness of the side rod toprovide for its non-binding passage therethrough.

While, as previously indicated, the three elevator slide member-side rodjoints shown in the drawings, but not specifically referred to here, arestructurally similar to that just described, they will differ, ofcourse, in nonstructural features, such as, in some instances, directionof the slide member from the pivot point of the side rod, etc. Thesedifferences are, however, of so trifling a nature as to require nofurther discussion and the structural character of each of thenon-described joints will, it is believed, be obvious from the foregoingdescription of the illustrative linkage mechanism consideredconjunctively with the drawings.

As explained above, elevator 18 rides up and down along fixed guiderails and through fixed limits of travel during operation of thepictured embodiment of my invention. Pivoted side rods 48, 50, 52 and54, have been shown to rotate around fixed pivot points intermediatetheir ends with their outer extremities at all times in a combinedsliding and pivotal relationship with the pins (bolts) secured in thebottom four corners of the aforesaid elevator, respectively. To thispoint, the description of the drawings has proceeded in what could beconsidered a reverse direction, that is, from the structure farthestremoved from the control and actuating means of the pictured'mechanism,backwards through the chain of mechanical energy transmitting elementstoward the prime source of the energy. This would probably be an undulyconfusing method of description in many cases, but it is here felt tobe, by virtue of the unusual nature of the subject matter, lessconfusing than the more orthodox route of delineative progressionthrough a machine or mechanism from its power source and along the path,or paths, marked by the flow of mechanical energy therein.

Returning now to the detailed description of the drawings, the power formoving elevator 18 is transmitted to it, through the interlinkagearrangement between rods 48, 50, 52 and 54 and the upright slide membersof the elevator, from shaft 64. This is accomplished by means ofslide-pivot interengagement of the two ends of the shaft 9. with the twopairs of inner ends of the aforesaid side rods, respectively. It willthus be seen that each of the side arms act as a first-order leverthrough which a force applied to its inner end is transmitted at itsouter end to an upright slide member of elevator 18 to which that end ispivotally and slidably attached in the above-described manner. Shaft 64is of round cross section throughout its length, but has two annularshoulders near, and the same distance from, its two ends. respectively,beyond each of which it is of concentrically reduced cross section andpintle-like appearance and function. The annular shoulders are shown ate and f on FIGURE 4, the distance of each from the nearest end of theshaft being such as to provide ample, but not excessive, axial distancealong the pintle-like end of the shaft to nonbindingly accommodate theflanking inner ends of two of the side rods upon which the shaft acts.Hereinafter, the pintle-like ends of shaft 64 will be referred to aspintles g and h, respectively.

The mechanical linkages between pintles g and h and the inner ends oftheir cooperating side rods are quite similar structurally to thelinkages between the screws afiixed to the bottom ends of the elevatorupright slide members and the outer ends of the side rods. The linkagesat the two pintle sites are similar to each other, except that each isin mirror-image relationship to the other, and hence, for the sake ofsimplicity, only the pintle g connection, shown in enlargement in FIGURE8, will be here described in detail. The pintle h connection will beclearly understandable from the following description considered inconjunction with the drawings which illustrate it.

Turning now to the drawings, and particularly FIG- URE 8, it will beseen that pintle g passes transversely through slotted openings in siderods 48 and St the opening in the former being shown in solid line at48a and the latter in dotted outline at 50a. Slotted openings 48a and50a are transversely centrally located in their side rods 48 and 50,respectively, and are similar to their counterpart openings in the otherends of the side rods except not as elongate because of the shorterrange of longitudinal travel of the pintle relative to either side rod,by comparison, for example, with the range of longitudinal travel ofbolt 78, in a longer lever arm portion of side rod 48 than occupied bysaid pintle. The disparity in slot length between the shorter and thelonger lever arm of the side rod is explained by a well knownmathematical principle, which will be better understood after thefollowing description of the manner in which movement is imparted to theside rods, and ultimately to elevator 18, by shaft 64. It is, of course,implicit from the foregoing description that all of the slots in theshort lever arm sections of side rods 48, 50, 52 and 54 are of the samesize, shape and rod positioning, and that the same is true of all of theslotted openings in the outer extremities of the longer lever arms ofthe rods.

As FIGURES 4 and show, pintles g and h extend in oppositely pointingdirections substantial and equal distances past the planes of the facingsurfaces of their respectively adjacent spacer blocks, the primaryreason for this being to provide pintle axial distance safety marginssuflicient to preclude any likelihood of side rod slippage from the endof either pintle. To permit such pintle extension, spacer blocks 74 and76 are appropriately slotted as shown at 74a and 760, respectively, toprovide hollow spaces therein for pintle travel during operation of thepictured mechanism. Since, as will presenlty be considered in moredetail, shaft 64, in operation, travels a substantially vertical path ofoscillation, slots 74a and 7601 are both of vertical disposition toaccommodate this character of movement on the part of pintles g and h,respectively, therein. The two spacer block slots are equallydimensioned and, since, as previously indicated, shaft 64 extendstranversely across housing 2 in perpendicular relationship to its sidewalls, the slots are in mirror-image relationship relative to each otheron their opposite sides of the housing.

The above-noted vertical oscillating movement is imparted to shaft 64 byan oscillating arm 88 having a transversely central slot, as shown at83a, through which shaft 64 passes, and pivoted to a bracket 90 attachedto end wall 12 of the housing in the position shown on the drawings.Oscillating arm 88 is transversely centrally positioned within housing 2and disposed perpendicularly to shaft 64. It is pivotally fastened, bymeans of a pivot pin 92, of the well known type having end stops snappedinto mating grooves around its periphery to prevent migration of the pinfrom its work station during operation of the depicted mechanism, to alink 94 which transmits mechanical energy thereto from a crank to whichit is, in turn, pivoted. The pivotal connection between link 94 andoscillating arm $8 is located about one-third of the distance from thelinkage joint between the arm and shaft 64 to the pivotal connectionbetween the arm and bracket 99. Thus, oscillating arm 88 functions as asecond-order lever in that force is applied to it intermediate a pointof fixed pivotal support and a point at which the force is transmittedto another member, in this case shaft 64.

Bracket 96 is formed from relatively thin metal sheet stock in the shapeof an L, and is fastened to end wall 12 by two screws 8 and 100, whichpass through two holes in one of its legs to anchor it flush against thesurface of the wall, as shown in FIGURE 5. The other leg of the Lextends directly outwardly from approximately the vertical centerline ofthe end wall, and it is to this outstanding leg that oscillating arm 88is pivoted, this being accomplished by means of a short bolt 162 passingthrough aligned openings in the arm and bracket. Bolt 102 is maintainedin place by a nut 104 drawn to proper tightness to pull the arm andbracket sufficiently close together to prevent wobble of the formerduring its pivotal movement about the bolt, yet not so tight as tocreate binding frictional resistance between the arm and the bracket.

During operation of the illustrated embodiment of my automaticdeveloper, oscillating arm 88 is urged through radial oscillations aboutthe pivot bolt Hi2 by alternating up and down movements of the link 94,thus causing its outer end, to the right as viewed in the drawings, tomove continuously up-and-down through a narrow arc defined by the upperand lower positional limits of the arm shown in FIGURES 2 and 3,respectively. The elevational location of bracket 50 on end wall 10 isroughly halfway between the upper and lower swings of the outerextremity of oscillating arm 88 in its alternating up and down movement,as will be evident from a study and comparison of the arm positions inFIGURES 2 and 3. While this particular bracket position is notcritically acute for purposes of my invention, it represents a preferredoperating height for the pivoted end of oscillating arm 88 because thehorizontal component of travel of the outer, swinging end of the arm isminimal at this pivot elevation. This is desirable in order toapproximate, as nearly as possible, true vertical oscillation of theouter arm 38, and thereby substantially achieve that type of motion inshaft 64.

It will now be apparent that the up and down movements of elevator 18are brought about by the transmission of mechanical energy, from a powersource as yet undefined, through link 94 to oscillating arm 88, theenergy being so directed as to cause the arm to oscillate radiallythrough a narrow are about a fixed pivot. The unpivoted end of arm 88transmits its oscillating motion to transverse shaft 64, which in turntransmits it to the inner ends of side rods 48, 5t), 52 and 54 throughits slotpintle linkages therewith. Since, as previously explained, twoof the side rods are controlled by each pintled end of shaft ed, and thetwo on one pintle act in unison with their counterparts on the otherpintle, the motions of the four side rods responsive to the urging ofshaft 64 will be described by specific reference to rods 48 and 50, thetwo rods adjacent side wall 6 and illustrated in their positionalextremes in FIGURES 2 and 3.

Directing attention now to FIGURE 2, elevator 18 is there shown at itslowest position of travel, sometimes herein referred to as its lowerterminus, which, as might be evident from what has already beendisclosed regarding the principal purpose and manner of operation of thepictured embodiment of my invention, is its normal positional statusbetween programmed cycles of actuation thereof. Since the proceduralparticulars of the here-involved automatic developing process have notbeen clearly described as yet, it is necessary to note, at this point,that elevator 18 is at rest in its FIGURE 2 position most of the time,even during periods of active use of the automatic developer. Only atcomparatively rare intervals, which are determined in advance, andprogram-incorporated into an automatic control system for the developer,later to be explained in detail, is the elevator caused to rise from itslower terminus location, When the elevator finally does move, at thecommand of the aforesaid automatic control system, it typically makesonly one round trip to its highest point of travel, this beingillustrated as previously noted, by FIGURE 3, and then settles down torest at its lower terminus until again urged into action, after theproper time interval, at the bidding of the control system.

FIGURE 2 shows, better than words can explain, that l the designconfigurations, and interlinkage network, of

the various mechanical parts between shaft 64 and the four lower cornersof elevator 18 are such as to create an inverse-position relationshipbetween the outer end of oscillating arm 88 and the elevator in thesense that energizing movement of the former, in either the up or downdirection, is translated by the intervening channels of mechanicalenergy flow into a reverse-direction movement of the latter. This iswell illustrated by FIGURE 2, which shows a concurrence of low elevatorand high oscillating arm extremity positions, as well as by FIGURE 3,which shows just the reverse positional relationship be tween the twoparts.

Referring now to FIGURE 2 which, for reasons made clear above,represents the normal starting position for movement of elevator 18, theenergizing pulse for such movement is manifested, as a result of energyflow from a source subsequently to be disclosed, to link 94 by adownward pull on pivot pin 92 by said link. This pull, acting throughthe pivot pin, causes oscillating arm 88 to swing downwardly about itspivot point at bracketed bolt 102 and, in turn, pull shaft 64 down atits slot 88a interlinkage therewith. The downward movement of shaft 64acting at the points of contact of its pintle g in slots 48a and 48b ofside rods 48 and 50, respectively, pulls the inner ends of those siderods down and causes them to pivot about their fixed pivot points atscrews 66 and '68, respectively. A clearer mental picture of the latteraction can perhaps be formed by looking at FIGURE 8, which shows anunobstructed view, in enlargement, of the inner ends of side rods 48 and50 in their FIGURE 2 positions.

The downward movement of the inner ends of side rods 48 and 50, andtheir consequent pivoting around screws 66 and '68, causes their outerends to see-saw upwardly and thereby urge elevator 18 in that directionas a result of pressure on upright slide members 20 and 22 at theirslide-pivot linkages with the side rods, respectively. This mechanicalchain reaction continues until link 94 reaches its lowest point oftravel, as illustrated in FIGURE 3, whereat the outer end of oscillatingarm 88 is also at its lowest point, which means that the inner ends ofside rods 48 and 50 have been forced to their lowest point and the outerextremities of these rods, and hence elevator 18, have reached theirzenith. The described series of events is followed immediately by returnof link 94 to its highest point of travel and consequent reoccurrence ofthose events in reverse sequence, in the sense that the parts move inopposite directions, to complete a full cycle of elevator travel andbring it to rest in its FIGURE 2 position.

After return of the elevator to its lower terminus, the actuatingmovement of link 94 ceases, under normal operating conditions, until itis again induced to perform in the described manner. Although alreadypointed out, it is repeated for emphasis that side rods 52 and 54function in unison with side rods 48 and 50, respectively, during thelifting and lowering of elevator 18. The only difference between theperformances of the two pairs of side rods, are that the former transmittheir forces to upright slide members 24 and 26, respectively, of theelevator, whereas the latter transmit theirs to slide members 20 and 22,respectively, and the former operate adjacent side wall 8, whereas thelatter operate adjacent sidewall 6, of the housing 2.

Suflicient detail as to the structure and manner of functioning ofelevator 18, its guidance hardware and that portion of its drive systemmechanism so far discussed, has been given to adequately reveal, withoutthe need of further elaboration, the total structural and mechanicalfabric thereby encompassed. Thus, certain things not heretoforeexpressly spelled out will nevertheless be fully apparent from theforegoing description, examples of such being the means and manner ofphysical support for elevator 18, the reason why shaft 64 is alwayshorizontally aligned, the geometrical necessity for the need ofslot-type openings at slide-pivot joint sites, to name a few. The termslide-pivot joint, as here employed, is a coined generic term which, forlack of a better one, is used to denote all joints in which a pivot, orpivot-like member, moves in a slot in a separate lever member, and itincludes the two similar, but slightly different, types of jointpreviously referred to herein as slot-pivot joints and slot-pintlejoints, respectively, and by other terms of similar import. While themechanical and structural aspects of the subject apparatus are many,because of the number and complexity of interengagement of the involvedparts, enough has been disclosed to teach, in conjunction with thedrawings, the structure and manner of functioning of the apparatus tothose skilled in the art.

Returning now to discussion of the flow paths for the transmission ofdrive energy to elevator 18, from a source as yet undefined, andproceeding in the reverse, or upstream, direction heretofore pursued,link 94 is pivotally fastened to crank 96 by means of a pivot pin 103,of the same type as pivot pin 92, with peripheral grooves around itsends into which stop members are snapped. Pivot 103 passes throughaligned openings in the link and crank members, the one in the linkbeing near its bottom end, and the other being longitudinally offsetfrom a receptive hole in the crank for a crankshaft 101 which extendsfrom a small gearhead motor 99. The relative dimensions of pivot pins 92and 103, and the receptive openings therefor, in the interlinked parts,as well as the spacing of the interlinked parts along the pins, are soadjusted as to permit free turning of the parts about their pivot pinsand relative to each other.

Link 94 and crank 96 are properly sized sections of metal bar stock,although they can be constructed of other suitable material ormaterials, such as any of those referred to above in the discussions ofsatisfactory alternative materials for construction of the structuralmembers of elevator 18, side rods 48, 50, 52 and 54, and other parts ofthe pictured apparatus. The outer end of crankshaft 101 has a flat spoton its periphery to provide an anchor base for a set screw, and this endof the shaft is fitted into a longitudinally off-center hole, previouslyreferred to, running perpendicularly through crank 96, the flat spotbeing oriented toward the nearest end of the crank. A set screw 97 isthreaded into a tapped hole in the end of the crank, connecting with theopening for crankshaft 101 therein, and tightened to locking contactwith the flat spot on the periphery of the crankshaft. This fasteningarrangement permits crank 96 to turn synchronously and in eccentricitywith, and in a plane perpendicular to, crankshaft 101.

Gearhead motor 99 is a small electric motor attached by bolt fasteningmeans, as indicated at a5, 93, 91 and 39 on the drawings, to the uprightleg 37 of an L-shaped support bracket positioned as shown with its otherleg secured to the floor of housing 2 by screw means (not shown).Crankshaft 101 extends outwardly from the gearhead motor 9% to itsabove-described connection with crank 96. The drawings, and particularlyFIGURES 2, 3, 4 and 5, illustrate the described arrangement of parts,and the means by which they are fastened in place and interconnected,within housing 2.

Gear motor 99 supplies energy to drive elevator 18 through its periodiccycles of travel while acting under the guiding influence of anautomatic control circuit which functions in a manner later to bedescribed. The motor thus acts as a servomechanism, which, upon receiptof activating impulses from the control circuit, automatically commencesto operate crankshaft 101, which thereupon transmits its motion to crank96, causing the latter to turn eccentrically around the axis of theshaft in the direction indicated by the curved arrows on FIGURES 2 and3. The crank, by virtue of its pivotal linkage with link 94, causes thepivot point of the latter to describe a circular orbit about the axis ofthe crankshaft. The circular travel of link 94 at this pivot point istranslated into reciprocative travel at its other pivot point (pivotalconnection with oscillating arm 83), the travel pattern of the latterbeing one of oscillation through a small, flat, and substantiallyvertical arc. There is a concurrence of high are point and high circleposition of the two pivot points on link 94, respectively, and the sameis true of the low points of pivot point travel, as FTGURES 2 and 3illustrate. One complete orbit of the lower (crank) pivot point of link94 corresponds to one complete oscillation (one up and one downmovement) of its upper (oscillating arm 88) pivot point.

The oscillating movement transmitted to oscillating arm 88 from link 94,through pivot pin 92, is further transmitted' through interconnectinghardware, the structure and manner of functioning of which have beenpreviously described in detail, to elevator 18, inducing the latter tomove in a direction determined by the direction of movement of theoscillating arm. It will be apparent to those skilled in the art thateach complete orbit of the lower pivot site of link 94 results in onecomplete cycle of up and down travel of elevator 18. Because of thissynchronization of movement, it is important to correlate the startingand stopping of motor 99 with the correct travel phases of elevator 18to assure automatic cut-off of the motor at the precise instant that theelevator reaches its lower terminus. With this kind of correlation, theelevator is in its proper position of rest between cycles of travel, andin the proper starting position to ascend when the motor again startsup. This kind of motor-elevator synchronization is not difficult ofachievement, as will appear from the description of the automatic motorcontrol systern to follow.

As previously explained, the relationship between the arcing movementsof oscillating arm 88 and the up and donw travels of elevator 18 isinverse, meaning that the extreme upward displacement of the armcorresponds with the lowest position of the elevator. Accordingly,FIGURE 2, which shows this orientation of parts, represents theheretofore discussed quiescent phase of the motor and elevator systemobtaining between the periodic excursions of the latter, and thestarting positions for all moving parts of the system awaiting startupof the motor. FIGURE 3, of course, represents the halfway, or upperlimit, point of the elevators travel cycle, and the correspondingpositional orientation of the parts of the elevator drive system at thatpoint.

It goes without saying that motor 99, crank 96, and link 94, as well asvarious items of accessory hardware for those parts, are all soconfigured, spaced within housing 2 and relative to each other, andgeometrically oriented to assure unhindered cooperation thereof towardthe common goal of feeding the proper kind and quantity of oscillatoryenergy to oscillating arm 88. The pivot hole locations in link 94 andcrank 96, as shown on the drawings, are merely illustrative, and notcritically definitive, of the possible pivotal arrangements for theparts in question. In this connection, those skilled in the art willappreciate that other pivot hole locations are operably possible, andthat no skill beyond that of the ordinary artisan to whom this teachingis directed is required for the selection of such hole sites. The samething is true relative to the selection of a suitable elevator drivemotor for purposes of my invention.

The principal requirement of the elevator drive motor is that it haveadequate torque capacity for the indicated purpose, and this is noproblem, since motors with such capacity are readily available on themarket. A preferred feature of the motor is that it have inherentbraking means to rapidly reduce its coast-down time when switched off.This feature is desirable in order to minimize the possibility ofelevator coast past its terminal station after switch-off of the drivemotor, as a result of momentum energy in the motor, and is found inthose cornmercially available motors which have built-in magneticbrakes. It is not essential, however, that the motor be self brakingsince, in the event it is not, it is well within the skill of theroutineer in the art to devise and apply an external brake of some sortto a suitably receptive moving part, such as crank 97 or crankshaft 101.As one example of such expediency, I have prepared a makeshift externalbrake by placing a helical spring, under tension, around crankshaft 101between the upright leg of motor bracket 87 and crank 96, with its endsbearing on those two members, respectively. The effectiveness of such abrake is enhanced by providing a layer of friction material, such asfelt, on the facing surfaces of the motor bracket and crank in the areasof helical spring contact therewith.

Although by now it will be apparent to those skilled in the art, it isperhaps worthy of note that the lift height of the side rods, and hencethe travel distance of elevator 18, can be varied by increasing ordecreasing the radius of circular orbit of pivot in 103 around the axisof crankshaft 101. This radial distance adjustment is easily made bysimply changing the longitudinal spacing between the openings for pivotpin 103 and crankshaft 101 in crank 96. Another way of accomplishingvariation in the lift height of the side rods is to vary the locationor" the pivotal connection between oscillating arm 88 and link 94 on theformer.

The anatomy of my automatic developer can be divided, for the sake ofdiscussion, into three principal subject matter areas, namely, (1) thearea of the abovediscussed elevator and its drive machinery, involving aconsideration of mechanical and structural features for the most part;(2) an area encompassing the X-ray developing capacity of the device,involving consideration of procedural, chemical, and plumbing sub-areas,as will later be seen; and (3) an area relating to the automatic controlsystem for the developer, the subsequent description of which willlargely involve electric circuitry and related sub-areas. The foregoingclassification does not neatly slice the whole pie into separate pieces,each distinct from the other, but loosely isolates certain easilyclassifiable categories of subject matter which diverge from centerareas of obvious contradistinction to outlying fringes which blend intoeach other to form twilight zones of overlap.

To this point, only the first of the above-listed categories of subjectmatter (elevator 18 and its drive mechanism) has been discussed.Proceeding now to the second, or X-ray developing category, attention isfirst directed to FIGURES 1, 2 and 3, which show the automatic developerin full-dress setup, complete with the necessary solution tanks for usein the development of dental X-ray plates. As previously indicated,FIGURES 1 III 23 2 and 3 show the two travel position extremes ofelevator 18. The purpose served by the elevator in traveling betweenthese two extremes is to advance a rack, or basket, 85, of dental X-rayplates from one liquid bath 33 to another 81, forwardly positionedthereof as shown. In this connection, FIGURE 2 shows elevator 18 at itslower terminus and rack 85 in liquid bath 33 at the proper depth tocompletely immerse X-ray plates carried thereby. The structure of rack85, and its means of support by the elevator will later be described indetail. For present purposes, it is only necessary to observe thatelevator 18 is so disposed at its lower terminus to support a rack ofX-ray plates at the proper immersion depth within a liquid bathpositioned as shown in the drawings.

While particulars of its specific accomplishment will be saved for laterdisclosure, it will be helpful to presently note that elevator 18carries rack 85 with it in its upward travel to the position illustratedby FIGURE 3. As the elevator approaches its highest point, rack 85 isurged forwardly relative thereto, and later, as the elevator descends,the rack moves still further in the forward direction until it isdirectly over the liquid bath just ahead of the one last evacuated asthe elevator approaches its lower terminus. From here, elevator 18gently rides into its lower terminal position, and, in so doing, easesthe rack into said liquid bath for its predetermined residence timetherein. FIGURES 2 and 3 partially illustrate this sequence ofoperations in that FIGURE 2 shows the starting point of the elevatortrip with basket 85 immersed in liquid bath 83, and FIGURE 3 shows theupper limit of the trip, at which point the basket has started itsforward movement relative to the elevator. Upon descent of the elevatorfrom the FIGURE 3 position, basket 85 will continue its forward movementuntil it is directly above liquid bath 81, into which it will settle asthe elevator moves to rest at its lower terminus.

Returning now to the description of the drawings, there are four liquidbath, as FIGURES 1, 2 and 3 show, within housing 2, supported on ahorizontal level and arranged in consistent alignment with thelongitudinal direction of the housing and transversely centeredtherewithin. These baths, two of which have previously been christened,are designated, from left to right, as they appear on each of theaforesaid figures, as 83, 81, 79 and 77, and they constitute bodies ofX-ray developer solution, firs-t rinse water, fix solution, and secondrinse water, respectively. The progress of the X-ray plates throughthese baths is in the order just set forth, that is, the plates arefirst immersed in the developer solution, then in the first rinse water,then in the fix solution, and finally in the second rinse water, afterwhich they are removed from the water and suspended in a stream of warmair to dry. The immersion time in each of the liquid baths isautomatically regulated for consistency with good X-ray developingpractice, and the drying time is likewise regulated, all in a mannerhereinafter described in detail.

The reason for the herein-taught program of alternating periods ofelevator movement and rest, as will now be clear, is to permit properlytimed immersion of the X-ray plates in each of the baths and toeffectuate the timely conveyance of the plates from each of the baths tothe next succeeding one by one round trip of the elevator to its upperlimit of travel and back. The exact manner in which the round trip ofthe elevator succeeds in conveying the X-ray plates from one bath to thenext remains to be explained, although the drawings probably make thisclear, particularly when considered in the light of the foregoingdisclosure. i

Liquid baths 83, 81, 79 and 77 are confined in vessels, or tanks, laterto be described in detail, and the tanks are supported on a platform 75,which is horizontally positioned within housing 2. at an elevationsufiicient to clear gear motor 99 and all of the elevator drivemechanism thereunder (which includes all of the mechanism except siderods 48, 50, 52 and 54, and portions of the ends of shaft 64) except theupper forward corner of oscillating arm 88 at its position of highestmovement during operation of the mechanism. However, to prevent jammingof this corner of the oscillating arm with the under surface of platform75, a slotted opening, which is shown at a and hereinafter referred toas slot 75a, is cut through the platform to give the necessary clearancefor unhindered travel of the arm. Slot 75a, asthe drawings show, runs inthe same direction as the longitudinal dimension of platform 75, istransversely centrally positioned in the platform, and is situateddirectly over the forwardly extending portion of said oscillating arm.

As will later appear, platform 75 is readily removable from housing 2,and slot 75a serves the purpose, in addition to that noted, of providinga finger-hold for grasp of the platform when inserting it into thehousing or removing it therefrom for repair or disassembly of theapparatus. Another opening is provided in the platform at 75b to permitupward protrusion of an elongated toggle switch lever 73, the functionof which will subsequently be discussed, therethrough. The opening inplatform 75 through which toggle switch lever 73 protrudes will behereinafter referred to as rectangular opening 75b.

Platform 75 is of wooden construction, although it could be made of anyother suitable material, such as one of the corrosion-resistantmaterials of the class of preferred materials of construction for theparts of'elevator 18, its drive system and other parts of the subjectapparatus setforth above. The property of corrosion-resistance is asimportant in platform 75 as anywhere else in the apparatus, for thereasons previously advanced in support of its desirability in partsfabricating materials. The platform is of generally rectangular shape,long enough to fit snugly, but not bindingly, in longitudinal alignmentwithin housing 2, but sufficiently narrow to permit its insertion into,and removal from, its position in the housing between long tie straps 28and 30 defining the upper longitudinal edges of elevator 18.

The maximum permissible width of platform 75 is, as a practical matter,determined 'by the distance between tie straps 28 and 33, since, as thedrawings make clear, it is necessary because of the internal arrangementof parts within housing 2, to take the route between those tie strapswhen moving the platform into or out of the housing. The exaggeratedheight of toggle switch lever 73, which suits it for a purpose later tobe disclosed, and the proximity of that member to the forward portion ofelevator 18, makes it somewhat difficult to maneuver platform 75 intoand out of housing 2, but with a little practice, this can easily beaccomplished when elevator 18 is in its upper, or FIGURE 3 position. Tobriefly explain, the platform is moved into position within hOuSing 2 byguiding its forward end between long tie straps 28 and 30 and undershort tie strap 32 (which defines the upper frontedge of the elevator)and, at the same time, taking care to see that toggle switch lever 73threads into rectangular opening 75b near its forward end, after whichthe platform is moved ahead until its rear edge clears short tie strap34, at the top rear of the elevator. From this point on it is a simplematter to jockey the platform into its proper place of rest in housing2.

Removal of platform 75 from the housing poses even less of a problamthan its insertion therein, and is accomplished by simply reversing,both chronologically and directionally, the steps of the abovedescribedprocedure. Platform 75 is supported within housing 2 by means of twowooden strips 71 and 69, aifixed to the facing surfaces of end walls 10and 12, respectively, of the housing. These strips hold up the ends ofplatform 75 in the manner shown in the drawings, and they are fastenedby nail means (not shown) to their respective backing walls, each at theproper elevation and in the proper directional alignment to support theplatform at an effectively operable height and positional orientationwithin housing 2. Each of the wooden strips is transversely centered onits backing I 7 wall, by which is meant centrally located width-wise ofthe wall. Strip 69 (at the rear of housing 2) is about as long asplatform 75 is wide, so that its ends do not protrude from under theplatform when it is at rest thereon as shown in FIGURES 1 and 5.

Wooden strip 71, on the front wall of the housing (end wall 10) isrecessed along its top to a depth roughly equal to the thickness ofplatform 75, and for a distance slightly greater than the platformswidth, to form a mating hollow into which the end of the platform canfit in snug but nonbinding relationship. This nesting interfit betweenthe platform end and the recessed support strip is well illustrated inthe drawings, and particularly in FIG- URE 1, wherein the non-recessedportions at the upper ends of the latter are shown at 71a and 71b,respectively. The principal reason for nesting one end of platform 75 inthe described manner is to secure it against sidewise migration from itscentral position within housing 2, which, as will subsequently beapparent, would militate against proper functioning of the developerapparatus. Without some sort of security against lateral movement of theplatform, such movement could take place within the limits of the fourupright slide members of elevator 18. The latter members, as thedrawings show, and will be appreciated from an understanding of thearrangement and juxtaposition of parts within housing 2, are situatedadjacent the lateral edges of platform 75, two to each side of theplatform and slightly outboard thereof. There is, of course, nopossibility of any of side rods 48, 50, 52 and 5'4 jamming againstplatform 75 at any phase of their movement during Operation of theelevator drive mechanism, because of the spaces provided between theside rods and the lateral edges .of the platform.

Directing attention now to liquid baths 8.3, 81, 79 and 77, whichcomprise, as previously indicated, bodies of developer solution, firstrinse water, fix solution and second rinse water, respectively, it isfirst noted that there is nothing critical about the chemicalcompositions of the developer and fix solutions. In this connection, anydeveloper or fix solution presently employed for dental X- raydeveloping processes is suitable for present purposes. For the foregoingreason, plus the commonly known fact that the chemistry of suchsolutions is either familiar to those skilled in the art or readilyaccessible to them in publications of which they are aware, and thefurther fact that the solution ingredients are commercially available toany-one with the purchase price, the solutions will be identified hereinonly by popular name and not by chemical composition.

Liquid baths 83, 81, 79 and 77 are confined in three plexiglass tanks,67, 65 and 63, so shaped, sized and assembled atop platform 75 as todefine separate zones of confinement for the baths. The confines of eachzone of containment are elongate and trough-like, and the zones run, inparallel adjacency, transversely across platform 75 for most of itswidth. Developer solution 83, constituting the bath to the rear of thehousing, or to the left of the line of baths as pictured in thedrawings, is contained in plexiglass tank 67, a rectangular, open-toppedvessel fabricated of precut wall and bottom sections of ..plexiglass,which are glued together at their meeting edges to form leakproof seamsof sufficient rigidity to hold the vessel together. Tank 67 forms theboundaries of one of the above-indicated liquid bath zones. Theboundaries of the other three zones are formed by tanks 65 and 63, whichare so sized and shaped as to permit interfit of the latter into theformer in the below-described manner.

Tank 65 is an open-topped vessel, formed of plexiglass wall and bottomsections in the same manner as is tank 67. However, it is sufficientlylarger than the latter tank to internally accommodate three, rather thanonly one, of the liquid bath zones, as the drawings, and particularlyFIGURE 1, Well illustrate. In addition to being bigger than tank 67,tank 65 differs therefrom in certain internal particulars, discussedbelow, and in the extensions of its side walls a short distance past itsfront wall to form a pair of wing-like members 59 and 61, respectively,which flank a small area to its immediate front. Tank 63 is the smallestof the three solution-containing vessels, and, like the other two isopen-topped and of rectangular shape. The internal width of tank 63 issubstantially the same as that of tank 67, but its length issufliciently shorter than that of the latter vessel to permit itsperpendicular endwise insertion in tank 65. The tolerances between theapplicable dimensions of tanks 63 and 65 are such as to permit insertionof the former into the other in the described manner with easily slidingclearance between the ends of the one and the inner sides of the latter.

As the drawings show, plexiglass tank 63, by virtue of its interfitrelationship with tank 65, and with the aid of certain cooperating partswithin the latter, later to be described, internests laterally acrossand longitudinally centrally within tank 65. The longitudinal axis oftank 65 runs parallel to that of platform 75, and it is thus apparentthat the described assembly of tanks yields three partitioned areas.These areas correspond to the three liquid bath zones of previousreference, the middle area, or zone, consisting of the space within tank63 and the other two comprising the spaces between its side walls andthe end Walls of tank 65, within the latter tank, respectively. Thesethree partitioned areas, and that within plexiglass tank 67, are ofroughly, but not exactly, the same size and shape, and in each instanceadequately capacious to receive rack and permit proper liquid immersionof its load of X-ray plates for purposes of this invention.

When smaller tank 63 is nested within larger tank 65 in theabovexiescribed manner, it does not rest on the bottom surface of thelatter vessel, but is suspended a slight distance thereabove, thusproviding open communication for liquid circulation between rinse waterbath zones 81 and 79, which, as previously indicated, occupy the spaceswithin tank 65 on either side of tank 63. It will, of course, by now beapparent that fix bath zone 79 comprises the area within tank 63. Itwill also be apparent that the first rinse water in liquid bath zone 81is not a separate body of liquid from the second rinse Water in zone 77,but that, instead, the two form a common body of Water in outerlysurrounding contact with the side walls and bottom of tank 63, theadvantages of which are at least two-fold, as will hereinafter beexplained.

It should be noted, at this juncture, that although no plumbing systemfor the bath tanks is shown on the drawings, and the pictured apparatuswill function satisfactorily without such, the preferred commercial formof my apparatus incorporates Water flow rate and temperature controls ofsuch character as to permit the constant flow of rinse water, maintainedat the proper temperature, through its two rinse water zones when sodesired. Controls of the indicated type can be easily installed asaccessories to, or for close cooperation with, the liquid bath assemblyof the automatic developer by one skilled in the art with the presentteachings before him. To illustrate, a water valve of the type used inshower baths can be plumbed into a hot and cold water input system forthe baths to maintain the inflowing water at a preset temperature.

Drain means are preferably installed and employed in the water rinsesystem of the developer where the inflow water controls of thesuggested, or other suitable, type are furnished. Such drain means makesit possible to maintain a constant flow of water, at the desiredtemperature, through the water bath zones. As previously indicated, andwill hereinafter be discussed in greater detail, liquid bath temperatureis a factor of some importance in X-ray developing technology. It shouldperhaps be pointed out that the installation and use of drain meansaccessory to, or in conjunction with, the rinse water facility of myautomatic developer burdens the ingenuity of one skilled in the art nomore, and possibly even less, than installation and use of the waterinput control means of above note.

For the indicated reasons, to wit, lack of criticality to functioningcapability of my automatic developer of a water control system and theready capability of one skilled in the art to install such a system, nofurther discussion of the plumbing, or other, particulars thereof willhere be attempted. In any event, whether or not accessory water flow andtemperature controls (by which is meant controls more or less a part ofthe developer apparatus, or closely allied therewith from the structuralstandpoint) are utilized, a prime advantage of the illustrated tankconfiguration is that it readily permits withdrawal of the developer andfix solution tanks (67 and 73) therefrom for emptying, cleaning, loadingwith fresh solution, etc., purposes, with minimal disturbance of eitherthe rinse water or its containing vessel (tank 65). A further advantageis that it helps to maintain a uniform temperature (which, as thoseskilled in the art will appreciate, is desirable) throughout the wholeliquid bath setup in that it permits the free circulation oftemperature-regulated water around the sides and bottom of the fixsolution tank (63) and in the adjacent vicinity of the developersolution tank (67).

Where flow and temperature controls are incorporated in, or used inclose conjunction with, the water bath system, the foregoing advantagesof the tank configuration are enhanced, since the presence of theresulting plumbing hardware makes it of even greater advantage to beable to remove the developer and fix solution tanks without disturbingthe water system, and the added control features insure bettermaintenance of desired water temperatures and, hence, better temperaturecontrol throughout the whole bath assembly. Additionally, theincorporation of water flow and temperature controls, including drainagemeans, into the water rinse facility, permits the continuous removal ofimpure water from the water bath tank since it can be continuouslyreplaced with inflowing fresh water.

The fix solution tank (63) is guided into, and maintained at, itslongitudinally central location within water tank 65 by the presence offour plexiglass stop blocks of equal size, 57, 55, '53 and 51. Thesestop blocks are fixedly secured by glue means in the side dihedralcorners of tank 65, and so positioned as to define the four corners ofthe space occupied by the bottom of tank 63 when it is properly berthedfor purposes of this invention. Tank 63 is supported at its ends, withinlarger tank 65, by two strips of plexiglass, 49 and 47, fixedly securedby glue means in the dihedral corners of tank 65 occupied by theaforesaid stop blocks, strip 49 running for most of the distance betweenstop blocks 57 and 55, and strip 47 similarly occupying the spacebetween stop blocks 53 and 51, which pairs of stop blocks are, as thedrawings illustrate, situated transversely opposite each other in thelarger tank. Plexiglass strips 49 and 47 do not rise as high as stopblocks 57, 55, 53 and 51, and this permits the latter members to serveas defining limits within which to guide tank 63 to its mooring positionwithin tank 65, and thereafter physically restrain the smaller tankagainst movement out of that position. Tank 63 is sulficiently lowerthan tanks 65 or 67 (which latter two are, as the drawings, illustrate,of equal height) to render its upper edges coplanar with the upper edgesof tank 65 when it is inserted therein. The purpose of strips 49 and 47is, as will be evident, to support the outer surface of the bottom oftank 63 a short distance above the floor of tank 65 and thus provideopen communication between water rinse bath zones 81 and 77.

FIGURES 2 and 3 show that there are four vertical channels, 14cm, 14ab,Mac and 14nd, within the 14a network of guideways separating the group14 arrangement of plexiglass section pieces on side wall 6. Thosedrawings further show that the said vertical channels are in substantialalignment with the longitudinal bisectors of liquid bath zones 83, 81,79 and 77, respectively. Since, as previously disclosed, guidewaynetwork 14a is matched by mirror-image network 16a defined by the groupof plexiglass sections on side wall 8, it follows that the fourabove-identified vertical channels have four counterparts in the 16anetwork of guideways, and that these are likewise in line with thelongitudinal bisectors of the four liquid bath zones, respectively.While the latter four channels (16a network) are not shown anywhere onthe drawings, such a showing is unnecessary in view of the fact thattheir locations have been given and it has been disclosed that they aremirror-image reflections of channels 14ml, 1412b, Mac and 14ad, whichare fully described and shown.

It is important that the alignment between the four above-describedpairs of oppositely facing vertical channels and the longitudinalbisectors of the four liquid bath zones, respectively, as well as thelateral spacing between the channels and liquid bath zone areas, bepreserved, for reasons later appearing. To effectuate this purpose, bycurbing the possibility of either sidewise or forward migration of theliquid-containing tanks during operation of the automtic developer,three sections of angle aluminum, 106, 168 and 110, respectively, arefastened to platform by nail means, only partially shown, atstrategically suitable locations. Angle section is fastened transverselyacross platform 75, with one flange flush against its upper surface andpointing forwardly toward the front of housing 2, and the other flangeextending outwardly, as shown particularly well in FIGURES 2 and 3, toprovide a barrier against forward movement of tank 65 and help positionthe forward edge of the tank for proper alignment of the liquid bathzone bisectors and the aboveidentified vertical channels in guidewaynetwork systems 14a and 16a, respectively. As FIGURE 1 shows, the lengthof angle aluminum section 110* is such as to substantially fill thenarrow space between the wing-like sections 61 and 59 of the side wallsof tank 65 (hereinafter called wings 61 and 59) yet leave sufficientclearance at its ends to avoid jamming.

Wings 61 and 59 are helpful aids to the proper seating of tank 65 onplatform 75. This is particularly important in cases where plumbingfixtures for a water flow control system are connected to the tank,since the tank must then, as a general rule, stay oriented in the samedirection to assure proper hookup with outside plumbing lines orfacilities. Wings 61 and 59 provide ready means for effectuating thistank orientation upon initial installation, or thereafter uponreinstallation of the tank after removal for cleaning, or other,purposes. In this connection, it will be apparent that the liquid tanksof the drawings are properly positioned in the automatic developer onlywhen wings 61 and 59 extend forwardly toward the front of the housing,since, otherwise, the wings would force the developer solution tank outof its proper position of alignment with the above-indicated verticalchannels in guideway systems 14a and 16a, and thereby render the apparatus inoperative for reasons later made clear.

Angle aluminum sections 106 and 108 are fastened along the side edges ofplatform 75, with one flange of each flat against the under side of theplatform and the other flange extending upwardly flush against a sideedge thereof. The two sections are of equal length and each stretchesfor most, but not all, of the distance between the position oftransverse aluminum section 110 on, and the rear end of, the platform.Sections 106 and 108 are made from angle aluminum of such size that theupstanding flange of each projects above the upper surface of platform75 for about half of its height to form a side curb of suflicientelevation to prevent sidewise migration of the liquid bath tankstherebeyond during operation of the automatic developer.

It has been explained above that the illustrated embodiment of myinvention functions by employing an elevator, and drive mechanismtherefor, to convey, in a manner not yet made completely clear, exposeddental X-ray plates from bath to bath through a series of liquid bathzones confined in tanks supported atop platform 75, the liquid bathscomprising conventional developer and fix solutions and water rinses,and thereby develop the exposed X-ray plates automatically. It has alsobeen pointed out that the X-ray plates are conveyed through theautomatic developing procedure in a rack supported throughout, in amanner hereinafter described, by the aforesaid elevator. Rack 85 is abasket-like structure of generally rectangular cross section andelongated form, so dimensioned as to fit easily into each of theaforesaid liquid zones with sufficient room to spare to permitunhindered circulation of the liquid therearound during operation of theapparatus.

The rack is made of plexiglass (although it can be of any suitablematerial inert to the liquid bath materials into which it is dipped inthe practice of the present invention) structural elements fastenedtogether by glue means so as to form an open topped-carrier of generallyhollowed-out interior, but having evenly spaced ribs, exemplarilyillustrated at i on the drawings (all ribs being so designated due totheir similarity) encircling its inner surfaces. The ribs i divide theinterior of tank 35 into a plurality of square, transversely parallelslots, as exemplified at 85a, all such slots being so designated becausetheir similarity, of predetermined size to admit dental X-ray plates,one toeach slot, in loosely nesting relationship. The outer bottom ofrack 85 has two longitudinal recesses 85b and 85c running for its fulllength, said recesses being spaced equidistantly from the center line ofthe bottom and penetrating as far as slots 85a. Longitudinal recesses85a and 850 thus provide openings in the bottom of each slot 85a topermit free circulation of the surrounding liquid through the rack andinto contact with the X-ray plates when carrier and plates are immersedin one of the aforesaid liquid baths.

Although rack 85, as drawn, includes only fifteen of the SSA slots,twenty such slots are required to hold one complete set of dental X-rayplates. The drawings are only intended to illustrate the carrierstructure, however, and it is felt to accomplish this better as itstands than it would if slots were crowded into the space now occupiedby 15, since such crowding would detract from the presently achievedclarity of illustration. Furthermore, the depicted type of carrier isonly one of many suitable alternatives within the scope of my invention.For example, the carrier could have a wire screen, such as a stainlesssteel screen, bottom, sides, or both, and this might even be superior tothe rack 85 construction in that it would permit freer circulation ofliquid around the X-ray plates during operation of my automaticdeveloper. Another alternative is the substitution of supported clips,which in turn support individual X-ray plates, for the above-describedrackor screen-type carrier. The clip arrangement permits completefreedom of liquid circulation around the X-ray plates, since there is nohardware structure to the block or hinder it.

Rack 85 is suspended from a round support rod 112, by hardware meanshereinafter described, of sufi'icient length to extend across housing 2and into transversely opposite grooves, or channels in guideway networks14a and 16a on housing side walls 6 and 8, respectively, to a sufiicientdepth to ride freely, without binding, therein, when urged to do so andmaintain at the horizontal during such movement. The rack is suspendeddirectly under support rod 112, and in transverse symmetry about itslongitudinal, and vertical, bisector, as the drawings well illustrate.Support rod 112 is metallic, preferably being made of acorrosion-resistant metal such as stainless steel, for reasonspreviously given in advancing the cause of corrosion-resistance inmaterials of construction for other parts of my automatic developer.

Rack 85 is suspended under, and locked to, support rod 112 by means ofthree strips of metal, preferably a corrosion-resistant metal such asstainless steel, 114, 116 and 118, respectively, bent and apertured inthe hereinafter indicated manner to suit them for their individualpurposes. The three strips are of equal width, this being slightly lessthan half the width of the rack 85, and two of them, 116 and 118, are ofequal size and shape, whereas the third, 114 is substantially differenttherefrom in both respects. Similar strips 116 and 118 are L-shaped andmuch smaller than strip 114, which latter consists of a relatively longcenter span, substantially equal in distance to the length of rack 85,terminating at each end in a upward bend, after which the strip rises tothe same height at each end of the center span and doubles sharply backupon itself to descend adjacently and parallely to its ascending portionand then to a point substantially below support rod 112, whereat it isbent at a 90 angle to form an inturncd flange directed toward the otherdescending end of the strip.

The long center span, ascending the descending end portions, andinturned end flanges of metal strip 114 are shown at 1', k, l and m,respectively, on the drawings, and particularly FIGURE 9. The L-shapedstrips 116 and 118 are each fastened with a downwardly depending legflush against, and in lateral edge alignment with, the outturned surfaceof one of end sections k and l of metal strip 114 by rivet means, asshown at 120 and 122, respectively, on the drawings, and an opposite legextending outwardly away from the end of strip 114 and on the same planeas long center span j of that member.

As will be apparent from the foregoing discussion of the involved parts,and as clearly depicted by the drawings, long center span and the twooutwardly extending legs of L-shaped strips 116 and 118 form asubstantially continuous bed, interrupted by upstanding partitions near5 each end comprising the ascending and'descending doubled back sectionsof metal strip 114 forming the upper portions of end sections k and l ofthat member, the aforesaid partitions being shown at ka and la on thedrawings. Hereinafter this continuous bed will be referred to as stripbed 124.

It has already been established that elevator 18 is automaticallycontrolled to make periodic trips to its high point of travel andreturn, and that it conveys rack -85 with a load of X-ray plates from aliquid bath zone to the next forwardly adjacent zone each time it makessuch a round trip. Support rod 112 rides on top of the elevator, as thelatter moves up and down through its vertical itinerary, carrying rack85, which is harnessed thereto by means not yet fully described, with itas it goes. The weight of the rod, rack and connecting harness means is,at all times, borne directly by parallel tie straps 28 and 311 at thetop of the elevator, across which said rod lies in perpendicularrelationship with its ends in oppositely posiitioned grooves, orguideways, of guideway network systems 14a and In this connection, andso that there will be no misunderstanding, the individual guideways ofguideway network systems 14a and 16:! are referred to herein variouslyas guideways, grooves, or channels, making those terms synonymous asapplied. Of the foregoing terms, guideways is perhaps the preferred one,since, as will presently appear, it is connotative of the purpose servedby the narrow spaces or passageways thereby denoted.

Returning now to the discussion of support rod 112 and its travel habitsin the illustrated apparatus of my invention, the rod at all times,whether riding on the elevator or merely lying across it in its positionof rest between trips, has each end captive, as previously indicated, inone of the guideways of the 14:1 and 16a guideway network systems. Thischannelure confinement of the ends of the support rod maintains the rodin perpendicularly transverse position within housing 2 at all timessince, as has already been made clear, the guideways of residence of itstwo ends at any given moment are directly opposite each other on theside walls of the housing, and the guideway networks of which they forma part, 14a and 16a, respectively, are mirror-image topographicalduplicates of one another, thus assuring identical travel of the twoends of the rod, in their separate but parallel planes of confinementwhen induced to movement by the time-table travels of elevator 13.'Since support rod 112 is mounted on the elevator in the above-describedpiggyback fashion, the latter obviously carries the rod through the samevertical distances that it, itself, traverses in the course of itstravels within housing 2. At the same time that the rod is ridingvertically on elevator 18, however, it is moving forwardly within thehousing, being guided in that direction by the sliding progresson of itstwo ends along charted passageways within the respectively imprisoningguideway network systems, the charted passageways being so laid out asto gently advance the rod ends the distance from one liquid bath zone tothe next in line during one round trip of the rod on the elevator. Thethreading of the ends of support rod 112 through the charted passagewayswill hereinafter be followed step by step. For the present, it is onlynecessary to understand in a general way the means by which support rod112 is steered forwardly within housing 2, thereby advancing rack 85 andits load of X-ray plates from one bath to the next during each lift anddescent of the elevator.

Continuing now with the description of the hardware connecting rack 85to support rod 112, attention is again directed to bent metal strips114, 116, and 118, which are fastened together in the above-describedfashion to form an elongated bed of strip metal, 124 with parallelyupstanding partitions ka and la, intermediate its ends, and dependingstrip sections, substantially coplanar With partitions ka and la andhereinafter referred to as depending strips kb and lb, respectively, ofequal length with inturned flanges m and n at their respective lowerends. The

space between depending strips kb and lb is sufiicient to accommodatethe length of rack 85 and the intended purpose of flanges m and n on thedepending strips is to grab and hold the ends of rack 85 in the mannerdepicted in FIGURE 9. To briefly explain, the ends of rack 85 haveaccommodating slots for the edges of inturned flanges m and n ofdepending strips kb and lb, respectively, the slots being so positionedas to assure level hang of the rack when supported in the describedmanner. To suspend'the rack in the illustrate-d fashion, it is merelynecessary to pass the inturned flanges of depending strips kb and lbinto their mating slots on the ends of the rack, by one means oranother, and then, if necessary, slide the fianges and rack relative toeach other to transversely center metal strip bed 124 and said rack onthe same vertical plane. The natural resiliency of any suitable materialof construction for depending strips icb and lb, many ex amples of whichwill be obvious to those skilled in the art, permits the snappingtogether of the inturned flanges of those strips and bracket 85 in thedescribed manner with no difiiculty.

Hereinafter, for the sake of simplicity, the whole strip assemblycomprising metal strip bed 124 and all parts appurtenant thereto asheretofore described and illustrated, will be referred to as harness126. It has previouslybeen explained that support rod 112 stretchestransversely across, and rides on, tie straps 28 and '30 at the top ofelevator 18. While this is in a sense true, it does not quite tell thewhole story since, as will now explained, and is illustrated in thedrawings, the support rod is cradled for a good part of its length onmetal strip bed 124, and the length of the strip bed exceeds thetransverse distance between parallel tie straps 28 and which support thewhole rack-harness-rod assembly. The rackharness-rod assembly issubstantially symmetrical about the plane of transverse bisection ofsupport rod 112 which means that the ends of metal strip bed 124 extendsuificiently far in each direction to come between the support rod andtie straps 28 and 30, respectively, at the points 2d of support of therod on those members, as illustrated in the drawings, and particularlyFIGURE 1. As the drawings also illustrate, support rod 112 istransversely cen trally positioned on metal strip bed 124 so that itslongitudinal axis lied directly over that of the bed.

The above-described, and drawing-illustrated, support rod-harnessconfiguration is designed to assure good balance and hang of thesupported rack, and the extension of the ends of metal strip 124 toover-reaching positional relationship with respect to the aforesaid tiestraps precludes the possibility of support rod roll on the tie straps,and consequent unbalancing of the rack from its proper position of hang.The support rod passes through aligned holes in upstanding partitions kaand la on metal strip bed 124, the holes being so sized and located asto receive the rod in tight friction fitting relationship and hold it inits proper position of cradle atop the strip bed, as illustrated in thedrawings, and particularly FIGURE 9. While the described friction fit ofthe support rod in the holes in the upstanding partitions ka and la onharness 126 is perfectly adequate for the purpose, the strength andtightness of the assembly can be enhanced by spot-welding the rod to theaforesaid partitions where it passes through the holes therein.

An explanation of the manner in which elevator 18 functions duringoperation of the drawing-illustrated embodiment of my invention has beengiven, although neither the automatic control system for the elevatornor its manner of operation have, as yet, been described or discussed indetail. This is consistent with the dilineative approach used herein,and explained above, in which the subject matter of my invention hasbeen divided into three general categories for separate treatment anddiscussion. Further in line with this approach, I will now proceed todescribe, for illustrative purposes, the step-byptep progress of a rackload of X-ray plates through the automatic developing process of myinvention as specifically carried out, in present contemplation, by thepictured embodiment of the automatic developer, again omittingdiscussion of the automatic control system of the developer.

Assuming the automatic developer is set up, plugged into a source ofelectrical power, and in all respects ready for use, it is normally putto use by first manually loading it with a rack of exposed X-ray plates,this being accomplished by inserting the plate-loaded rack, harnessed tosupport rod 112 in the above-described manner, into the rear end ofhousing 2 in the below-described manner. Elevator 18 should be at restat its lower terminus, as shown in FIGURE 2, when the rack of X-rayplates is inserted into the housing. The insertion of the rack assemblyis easily accomplished, as the drawings make clear, by lowering the twoends of the support rod into wide-mouthed entrance ways, shown at Moreand 16m: on the drawings, and hereinafter designated in that fashion,

'to the guideway network systems 14a and 16a on the two side walls ofthe housing. The rack assembly is inserted rack down and with supportrod 112 substantially horizontal. From wide-mouth entranceways l iae and16ae the support rod is slipped down through twin angled guideways inmirror-image relationship on the opposite side walls of the housing, onesuch being illustrated in FIGURES 2 and 3, to connecting verticalchannels pointing, on opposite sides of the housing, towards the longitudinal axis of plexiglass tank 67 filled to the proper level withdeveloper solution.

I One of the aforesaid vertical channels is shown at Hall on FIGURES 2and 3, its mirror-image counterpart on the opposite side of the housingnot being visible in any figure of the drawings. As previouslyexplained, however, the location, size, andother particulars ofthe-latter channel are readily comprehensible from the pictorialillustration of channel 14am and the foregoing description of guidewaynetworks 14a and 16a, the latter of which it 25 vertical channels untilthe support structure for the assembly comes to rest on the straps 28and 30 of elevator 1.8 in the position shown in FIGURE 2. At this point,the rack and its load of X-ray plates is fully immersed in the developersolution bath in tank 67 and the chemical plate developing process nowbegins. While the X-ray plates in rack 85 have not always heretoforebeen expressly referred to as exposed plates, it will be understood, ofcourse, that they have obviously been previously exposed.

After the rack load of X-ray plates has been lowered into the developersolution in the described manner, the automatic developer takes over andautomatically performs subsequent steps until the plates have been fullyprocessed and dried. Without going into any further control detail atthis time, the whole procedure is initiated by the flip of a panelswitch which activates the control system for regulating the immersiontimes of the plates in the various liquid baths, etc. Returning now tothe description of the mechanics of the developing process itself, afterthe rack of X-ray plates has remained in the developer solution for theproperly predetermined period of time, the drive motor for elevator 18is automatically activated, causing the elevator to rise and lift therack assembly with it. As the assembly ascends with the elevator, theends of support rod 112 ride upwardly in channels 14cm and itscounterpart on the opposite side of the housing to the lower edges ofcounterpart sections of plexiglass sections in groups 14 and 16 of thechannel-forming plexiglass sections on opposite side walls of thehousing respectively, which lower edges slant upwardly and forwardly toa high point at which each levels out into a shallow curve, theplexiglass section in group 14 being shown at 128 in the drawings, andits counterpart section in group 16 at 130. Hereinafter, for the sake ofsimplicity, the movement of only the end of support rod 112 traveling inthe 14a guideway network system, shown topographically in FIGURES 2 and3, will be described, although it is to be understood that the other endof the support rod is similarly moving through a mirror-image maze ofpassageways on the opposite wall of the housing.

As the elevator continues to ascend beyond the point at which theappropriate end of support rod 112 has contacted the upwardly slantingunder edge of plexiglass section 128, that end of the rod rides upwardlybut is urged in the forward direction, or to the right as seen on FIG-URES 2 and 3, by its moving contact with said slanting edge, thismovement being accelerated as the rod end rounds the curved section atthe upper end of the edge. The slanting and curving lower edge ofplexiglass section piece 123 is so contoured, the piece is sopositionally oriented on housing side wall 6, and the upper travel limitof elevator 18 is so fixed that coincidentally the end of support rod112 in contact with, and being deflected by, said lower edge as theelevator ascends, moves along that edge to the far end of its curvedportion, the curved portion being shown at 128:: on FIGURE 2 andhereinafter designated as curving edge 128a, and the elevator approachesand reaches its zenith. Thus, both the end of the support rod and theelevator arrive at their upper destinations concurrently, this jointarrival being illustrated in FIGURE 3 which shows the positions of thosetwo parts at exactly that time.

After reaching its FIGURE 3 position, elevator 18 begins to descend, asa result of which support rod 112 rides straight down on top of elevatortie straps 28 and 3-0 until its appropriately oriented end contacts adownwardly and forwardly sloping upper edge 132a of a plexiglass sectionpiece 132, one of a horizontal line of similarly-shaped section pieceswithin the group 14 display of plexiglas sections on housing side wall6. The elevator continues its descent after the support rod makes itscontact with sloping edge 132a as described, and this causes the rod toride forwardly on tie straps 28 and 30 at the top of the elevator, beingurged to do so by the cam-like interaction between the sloping edge andthe support rod end. The end of the support rod follows edge 132aforwardly to where it intercepts a defining boundary of the verticalchannel 14x11), which channel, as previously indicated, is directedvertically downwardly toward the middle of the first water rinse bath81, as shown in FIGURES 2. and 3. The intercepted boundary of channelldab is, additionally, one of the edges of plexiglass section piece 132,a pentagonally-shaped piece, as the drawings show. Its point ofinterception by sloping edge 13211 is shown at 13% in FIGURES 2 and 3,and will hereinafter be referred to as interception point 132]).

As the elevator continues to descend, the end of support rod 112 incontact with sloping edge 132a passes interception point 132b, afterwhich the end of the rod follows channel ldab vertically downwardly to alower terminal position therein. At that position, the rack assembly isat rest with the rack suspended within first water rinse bath 81 to thesame depth as figure shows it immersed in developer solution 83.Elevator 18 has simply completed a round trip to its apogee and back,and has thus come to rest at the same position as that shown in FIGURE2. It will remain at rest until automatically forced by its drivesystem, after a predetermined rinse time for the X-ray plates in zone81, to repeat the round trip to its upper terminus and back. The rack ofX-ray plates has been circuitously conveyed by the elevator ride fromimmersion in developer solution 83 to immersion in first rinse waterbath 81.

Enough has now been given by way of description, it is believed, tofully reveal the nature and physical particulars of the tortuous pathsof progression of each end of support rod 112 through the 14a and 16aguideway channels, respectively, especially when FIGURES 2 and 3 of thedrawings, which map the Ma paths, are conjunctively resorted to. Whileit will be obvious to one skilled in the art, it is nevertheless pointedout that the invention is not limited to the particular guideway layoutof the drawings, and that any system of conveying support rod 112, orits equivalent, through a path leading from an immersion station for oneliquid bath to a similar immersion station over another liquid bathincrementally advanced from the first, falls within the structural andfunctional scope of the invention. All that is necessary in such aguideway maze is that deflecting barriers be so placed as to effectcam-like guidance of the support rod ends in the proper directions tosteer them through passageways provided therefor within the maze.

Rack 85, with its load of X-ray plates, remains immersed in the firstrinse water bath for the properly predetermined period of time inaccordance with the programrned instructions to the automatic controlsystem for the elevator drive mechanism. The length of the water rinseresidence time, as is also true of the residence times in the otherliquid baths of the X-ray developing process, has no relevancy insofaras the present discussion is concerned, since it has nothing to do withthe critical structural or functional aspects of my automati developeror its method of operation, and the developer will operate effectivelyregardless of the lengths of any of the applicable immersion times. Forthis reason, plus the fact that those skilled in the art are well awareof, or can easily ascertain, proper immersion times for particular X-raydeveloping baths, no further comment on that point is here feltnecessary. Suffice it to say that once having ascertained the proper ordesired immersion times for the involved liquid bath, it is a simplematter to program these times into the automatic control system of myinvention by known timing, or equivalent, techniques, as will appearfrom the description of my control system to follow.

Turning now to the description of the manipulative steps performed by myautomatic developer in processing a batch of exposed X-ray plates,elevator 18 is again induced to action after expiration of the aforesaidresidence time of rack 85 in the first rinse water bath, as a result ofwhich it repeats the above-described trip to its upper limit of traveland back, concurrently conveying support rod 112, and its suspended rackload, through a circuitous path of travel identical to that justdescribed, in which the rack assembly was conveyed from the developersolution bath to the first rinse water bath, except removed onebath-unit increment forwardly thereof. By bath-unit increment, as thatterm is here employed, is meant the distance from left to right throughguideway system 14a, as viewed in FIGURE 2 or 3, representing the spacebetween the longitudinal bisector of one of the liquid bath zones tothat of the one adjacently to its right, in this case, the space betweenvertical channel 14ab and vertical channel Mac.

It is only necessary to compare the passageway followed by thehere-involved end of support rod 112 from its low position in channel14m to its low position in channel 1411b with the passageway through thenext bath unit increment from the 1441b to the 14cc vertical channel, tosee that the routes are identical, with equivalently designed andinternally positioned guide barriers. For example, curving edge 123a,section piece 132, downwardly sloping edge 132a and interception point1321; serving to define the passageway through which an end of supportrod 112 is threaded for conveyance of the X-ray plates from thedeveloper bath to the first rinse water bath are matched precisely,design-and layout-wise, by curving edge 134a, section piece 136,downward sloping edge 136a, and interception point 136b. The latterguideposts serve to define the passageway for the support rod endthrough the bath-unit increment leading from the first rinse water bathto fix solution bath 79.

Upon completion of the last-indicated cycle of travel, the rack-load ofX-ray plates is permitted to remain immersed in the fix solution bathfor a programmed interval of time, and then the elevator automaticalyrepeats its ritual of up-and-down travel, at the same time conveying therack through another bath-unit increment to deposit the same in thefourth and final bath, this being the second rinse water bath, shown at77 on the drawings. Here again, the passageway for routing theappropriately oriented end of support rod 112 from its low position invertical channel 14ac to that in 14ad, which is directly over the secondrinse water bath 77, is identical to each of the previously describedpassageways through the first two bath-unit increments of guidewaynetwork system 14a. This will be evident from an inspection of themapped layout of that guideway network system in FIG- URE 2 or 3.

As in the case of the previous three immersions, the rack and its loadof X-ray plates remains in the second rinse water bath for a prearrangedperiod of time, after which the elevator drive system is againautomaticaly activated, and the elevator once again ommences its upwardjourney. The forward progression of support rod 112 as it is beinglifted by the elevator to its high point of travel is similar to thatheretofore discussed in connection with the incremental conveyance ofthe rack of X-ray plates from each bath in the developing system to thenext, and the passageway followed by the end of the support rod captivein the 14a guideway network system is similar to its counterpart in thepreviously mentioned bath-unit increments thereof to its high point ofcurvature shown on curving edge 138a, which corresponds to previouslymentioned curving edges 128a and 134a. Beyond that point, the passagewayis different from those previously described because of the substitutionof a differently shaped piece of plexiglass 140 for the familiarpentagonally-shaped section exemplified by section pieces 132 and 136heretofore appearing at this juncture.

While section piece 140 has upper bounding edges somewhat similar tothose of section pieces 13?. and 136, including a sloping edge 1400similar to each counterpart edges 132a and 136a on the aforesaid sectionpieces, respectively, it, additionally, has an upstanding leg 14012rising from a point of interception of its inner edge with sloping edge140a and terminating at the top on a level even with the top of sidewall6 (as, incidentally, do those plexiglass sections Within group 14 whichform the top row of the group). As FIGURES 2 and 3 clearly show, wherethe inner edge of leg 1443b of plexiglass section 140 interceptsdownwardly sloping edge 1401: a pocketlike notch, shown at 1400, andhereinafter designated as notch 1400, is formed.

As the moving end of support rod 112 starts to descend with the elevatorafter its upward progression to the far end of curving edge 138a, itdrops down to eventual contact with sloping edge 140a and then followsthat down to its point of interception with leg 14012 at notch 140e,whereat it is caught and held. The elevator continues to descend,leaving the support rod suspended at the level of notch 140c which is,as the drawings show, high above the liquid baths and closest to, but tothe right of, the second water rinse bath. The movement of support rod112 to its notch 1400 position of entrapment brings rack into pressingcontact with lever 73 of the previously mentioned drying switch, whichis so sized and positioned within housing 2 as to make such contactpossible. Drying switch lever 73 is urged to the right, as viewed in thedrawings, by the weight of rack 85, and this causes the switch itself,shown at 142 in screw-fastened position on the floor of housing 2, toenergize a hot air blower 144 and thereby create a stream of warm air todry the X-ray plates as they hang suspended in rack 85. The hot airblower is fixedly secured, by suitable means, to the inner surface offront end wall 10 of housing 2, at such elevation and wall position asto best serve its purpose. A preferred blower arrangement is shown inthe drawings, which depict blower 144 so sized, positioned and ducted asto bath rack 85 in a stream of warm air flowing downwardly at the rightangle to carry moisture from the rack and X-ray plates toward the secondrinse water bath zone.

After a predetermined drying period, the X-ray plates are ready to beremoved from the apparatus. A warning signal light, which isautomatically controlled to go on at the beginning, and off at the endof the drying period, forms a part of the automatic control circuit ofthe developer. The circuit particulars of the blower and signal lightunits of the developer will be postponed pending later discussion of itsautomatic control circuit in detail.

Before leaving the subject of rack movement within the automaticdeveloper, it is pointed out that access can be had to any of the bathzones in the illustrated embodiment thereof through entranceways into'guideway networks 14a and 16a for the ends of support rod 112.. Two ofthese entranceways 14ae and 16ae, have already been discussed. Exemplaryof the others are entranceways 14a Mag and Mali, which admit one end ofsupport rod 112 to permit lowering of rack 85 into the first rinsewater, fix solution, and second rinse water bath zones, respectively.There are various reasons why it is sometimes desirable to gain accessto one or more of the bath zones in this fashion, none of which need bediscussed here. My automatic developer is not limited to use with fourliquid baths as shown in the drawings, and can be employed with fewer ormore baths for X-ray developing purposes, or other dipping procedures towhich the apparatus lends itself after relatively minor modifications,well within the ordinary oapabilities of those skilled in the art, ofthe equipment, procedures, or both, taught herein.

Turning now to the third major subject matter area of my invention, asit is outlined above, namely,the automatic control system for thepictured developer apparatus, attention is first directed to the FIGURE10 circuit diagram of that system, which shows all of itse1eotricalc0mponents and the manner in which they are wired together toaccomplish their cooperative purpose. All of the components of thecircuit diagram, except the manual override switch, are illustratedelsewhere in the drawings, the latter being omitted because it is anoptional feature *andrelay switch 15% with its actuating not necessaryto proper functioning of the control system, and also since the choiceof manner and place of installation of the override switch in thecontrol circuit is well within the ordinary capabilities of one skilledn the art, particularly in view of the FIGURE teaching of an operativelocation for such a switch in the circuit there depicted. While, :asindicated, all components of the FIG- URE 1O circuit except the manualoverride switch are variously illustrated throughout the drawings, noattempt has been made to show the connective wiring of the componentsanywhere except in the FIGURE 10 circuit diagram. The chief reasons foromitting the wiring from the drawings (other than FIGURE 10) are theextreme difficulty of attempting to pictorially show the spaghetti-likemass of wires interconnecting the various components of the electricalcircuit; the confusion which would result from inclusion of all thesewires in the drawings; the teaching of the wiring arrangement for thecircuit in FIGURE 10; and the fact that no one skilled in the art wouldhave serious difiiculty in constructing the FIGURE 10 circuit mm thetotality of teachings herein.

Electric power for the openation of the illustrated embodiment of myautomatic developer is obtained from a 1i5-volt A.C. current source, bymeans of a standard plug connector, not specifically illustrated, butsymbolized at 146 in FIGURE 10 by the pair of wire terminals thereindicated. The current is fed into the control circuit through a panelswitch 143, which is maintained in the off, or open circuit, positionduring non-use of the automatic developer, and flipped on to put theunit in operation. As the wiring diagram shows, a cam switch isconnected in series inthe circuit with panel switch 148. Cam switch 150comprises a rotatable cam disc 150a and a relay switch 15% with a springlever actuating member 150M, these parts being anchored, within a walledenclosure 156, to the floor, and near the front end, of housing 2, asshown in FIGURE 4. Cam switch 156 is oriented with its cam discparallelwith front wall It) of housing 2, member 15mm angling upwardly andcontacting the rim of the cam disc under a slight tension.

Cam switch 159 operates off of a timer motor 158 to which it isconnected by drive means. The timer motor causes cam disc 150a to slowlyrotate in such direction that its outer rim continuously moves out fromunder the end of spring lever actuating member 15tiba of relay switch15011. The purpose of cam switch 150, as will later appear, is to shutoff the whole unit after a certain predetermined period of time. Toeffectuate this purpose, the peripheral edge of cam disc 150a is sopositionally notched, relative to the shaft speed of the timer motor158, as to bring the resulting notch into alignment with the outer endof spring lever actuating member 1505a, after lapse of the aforesaidpredetermined time period. Cam switch 150 remains closed so long as theouter end of spring lever actuating member IStlba rides on theuninterrupted edge of its cam disc. However, when the movement of thecam disc brings the notch in its rim into coincidence with the outer endof lever member 15tlba, the tension on the member forces its end intothe notch. When this occurs, the inner end of the member is displacedsufliciently to cause the opening of relay switch 15%, thus interruptingthe flow of current in the circuit. How this fits into the operation ofthe control circuit will be better understood as the description of thecircuit proceeds.

When panel switch 148 is flipped to its on (closed circuit) position toplace the automatic developer in operation, switch 150 is in its closedcircuit position and its notched disc is so positionally calibrated asto bring the de-activating notch on its peripheral rim intoswitch-opening alignment with spring lever actuating member 1501M at theprecise moment when the time required for the developing and drying ofthe X-ray plates in the apparatus in accordance with the teachingsherein has expired.

Consequently, after the processing of X-ray plates has run its fullcourse in the developer, cam switch automatically opens the controlcircuit, thus shutting down the whole system. The only purpose of camswitch 150 is to effectuate this final de-activation of the controlcircuit, hence it remains closed during the entire cycle of operation ofmy automatic developer. Since the time requirement for full-cycleoperation of the developer will vary, depending, among other things,upon solution ternperatures, which have an effect on X-ray plateimmersion times, it is desirable to have some means of adjusting theinitial peripheral distance on cam disc 156a between the point ofcontact of spring lever actuating member 1591M thereon and theswitch-opening notch of above reference, to thereby regulate the totaloperation time of the apparatus. This is accomplished by means of apointer 160, rigidly secured to the end of a shaft 162 in perpendicularrelationship thereto. Shaft 162 is sulficiently long to extend from apoint in front of housing 2 through its front end wall and to coactiveand coaxial connection with cam disc 159a, whereby turning of thepointer, and hence shaft 162, turns the cam disc through the sameangular displacement. To reach cam disc 150a, pointer shaft 162 extendsthrough, in addition to front wall 10 of housing 2 already mentioned,the front Wall of enclosure 156, which, as previously indicated,encloses cam disc 159a, and another cam disc 166a disposed parallel to,and in coaxial alignment with, cam disc 150a. The shaft is hearinglysupported in appropriately aligned openings in front wall ll) of housing2 and the front wall of enclosure 156, and is connected to cam disc 166ain the same coactive and coaxial relationship that it bears to cam disc150a. This shaft penetration of the intervening barriers between pointerand cam disc 150a, as well as its connective relationship with cam disc166a, is shown in the drawings. The drawings also show various hardwareitems which are employed in the assembly, but these need not bepresently discussed because the nature, manner of use, and function ofeach will be readily understandable to those skilled in the art from thedrawings alone. Cam disc 166a, and its complementary parts and function,will hereinafter be described in detail.

As FIGURES 1 and 4 show particularly well, the length of shaft 16a issuch as to position pointer 160, which is affixed to its outer end, asearlier noted, in close adjacency to the outer surface, or panel, offront wall 10 of housing 2, but with sufiicient clearance between thepointer and the wall to permit non-binding rotation of the former aroundthe axis of the shaft. A panel dial 170 is fastened flush against theouter surface of front wall 19 of the developer housing, the dial beingpositioned within the sweep range of pointer 160 and offering aselection of time readings, the exact nature of which will besubsequently discussed. Suffice it now to say that the pointer and dialprovide a means of regulating the operating condition-s within thedeveloper through adjustment of the time schedule to be followed by itsinternal working parts. The actual timing of the various steps involvedin my automatic developing process, which, as will be apparent from theabove, forms a part of my invention, is accomplished through calibrationof cam disc 166a, further discussion of which will be postponed untillater. The timing of a complete cycle of operation of the developer isregulated by cam disc 150a, which is adjusted to a preselected timesetting by means of pointer 160 and interconnecting shaft 162.

The dial on the front panel of housing 2 has time readings for pointerselection and concurrent adjustment of the position of cam disc 166a forperformance consistent therewith. Cam disc 166a, as indicated above,controls the timing of the various procedural phases of my automaticX-ray developing process and, hence, dial 170 has time readings directlytied in with this function, typical of which are developer solutionimmersion times. While dial 170 typically reads in such a way as tofocus attention

9. AN AUTOMATIC DENTAL X-RAY PLATE DEVELOPING APPARATUS COMPRISING, INCOMBINATION: (A) CONTAINING MEANS FOR A PLURALITY OF X-RAY DEVELOPINGSOLUTION BATHS; (B) SUPPORT MEANS FOR SAID CONTAINING MEANS FOR SAIDBATHS; (C) ELEVATOR MEANS ADAPTED TO MOVE UP AND DOWN THROUGH A FIXEDPATH OF TRAVEL, AND SUPPORT AND MOVEMENT GUIDANCE MEANS THEREFOR; (D)ELEVATOR DRIVE MEANS, INCLUDING PRIME MOVER MEANS AND MOTIVE POWERTRANSMITTING MEANS INTERCONNECTING IT WITH SAID ELEVATOR MEANS SOCHARACTERIZED AS TO INDUCE THE LATTER TO MOVE THROUGH ITS FIXED PATH OFTRAVEL UPON ACTUATION OF SAID PRIME MOVER MEANS; (E) HOLDING MEANS FORDENTAL X-RAY PLATES SO SHAPED, SIZED AND POSITIONED AS TO HOLD THEPLATES IN ANY SPACE WITHIN SAID CONTAINING MEANS FOR SAID BATHS ADAPTEDTO CONTAIN A BODY OF BATH SOLUTION, AND SO CHARACTERIZED AS TO PERMITCONTACT OF BATH LIQUID SOLUTION THEREIN WITH SAID X-RAY PLATES DURINGOPERATION OF SAID DEVELOPING APPARATUS; (F) SUPPORT AND CARRYING MEANSFOR SAID HOLDING MEANS ADAPTED TO REST ON SAID ELEVATOR MEANS AND RIDEIT, IN HORIZONTALLY SLIDING RELATIONSHIP, AS IT TRAVELS UP AND DOWNTHROUGH ITS FIXED PATH OF TRAVEL, SAID SUPPORT AND CARRYING MEANS HAVINGOUTWARDLY EXTENDING PROJECTIONS; (G) GUIDE MEANS ADAPTED TO ENGAGE SAIDOUTWARDLY EXTENDING PROJECTIONS AND INDUCE THEM TO TRAVEL FORWARDLY APREDETERMINED DISTANCE DURING EACH UP AND DOWN TRIP OF SAID ELEVATORMEANS, THEREBY CAUSING FORWARD PROGRESSION OF THE ASSEMBLY COMPRISINGTHE SUPPORT AND CARRYING MEANS FOR SAID HOLDING MEANS. THE HOLDING MEANSPROPER AND ANY DENTAL X-RAY PLATES HELD THEREBY SAID PREDETERMINEDDISTANCE WITH EACH UP AND DOWN TRIP OF SAID ELEVATOR MEANS DURINGOPERATION OF THE DEVELOPING APPARATUS, COMPRISING: (1) A PAIR OFWALL-LIKE MEMBERS DISPOSED EITHER SIDE OF SAID SUPPORT AND CARRYINGMEANS IN GENERALLY PARALLEL RELATIONSHIP, THE FACING SURFACES OF SAIDWALL-LIKE MEMBERS BEING DISTINGUISHED BY THE PRESENCE OF GUIDE-WAYCHANNELS FOR SAID OUTWARDLY EXTENDING PROJECTIONS, THE CONSEQUENTCHANNEL PATTERNS ON THE TWO WALL-LIKE MEMBERS